General Purpose and Validation of this Standard Motivation – Provincial regulators require that gas production from all hydrocarbonproducing
wells be reported to allow proper management of gas resources. Solution gas volumes associated with oil production are generally reported as a Gas to Oil Ratio
(GOR), based on periodic well tests, with the GOR assumed to be relatively constant between tests, and gas volumes are then estimated, or measured and prorated, based on the measured oil production. For low rate heavy oil wells under primary or secondary production the volumes of gas produced and GOR’s are not very large in comparison to other types of production, but historically have shown a tendency to fluctuate wildly from test to test. The GOR fluctuations have resulted in a great degree of uncertainty in the reported GOR’s, and have also shown a great deal of inconsistency between companies with operations in the same pools, for which solution GOR’s should be similar. With increasing pressure to conserve vent gas and minimize greenhouse gas (GHG) emissions, there is a growing need to better understand the vent gas variability and ensure that GOR’s reported are representative of the actual volumes being produced. A solid understanding of vent volumes will help to prioritize vent reduction efforts and also to ensure that the most sustainable methods are used to mitigate the vents through balancing environmental, economic and local needs of all stakeholders. Standard Development Process – This standard was developed through a Joint Industry Project initiated in October, 2002 by Nexen, Inc. and funded by major conventional heavy oil producers: Nexen, CNRL (incl. input from Petrovera), Husky, ExxonMobil. It was developed to address the inconsistencies in vent gas testing and estimating practices between the various heavy oil producers in Alberta and Saskatchewan. The work was conducted by New Paradigm Engineering Ltd, through collection of data from participants and evaluation of the various testing and estimation methods used by producers. It was determined that much of the variation in solution GOR’s being reported are mainly due to inconsistent testing and estimating methods between heavy oil producers, as well as variations in gas production behaviour from these wells over the well’s producing life.
This standard is intended as a guide for producer field operations and technical personnel to improve consistency in estimating conventional (non-thermal) heavy oil solution gas volumes that are produced, used as fuel or vented on the well leases. Provincial and other regulations and guides, as revised from time to time, take priority over this document. While the study participants represent major players in conventional heavy oil production, this standard has not been formally adopted by CAPP or any other industry association.
Conventional Heavy Oil Vent Quantification Standard 2004:
Conventional Heavy Oil Vent Quantification Standard 2017: